Cole-Parmer Refillable Probe Potassium Ion Selective Electrode

Cole-Parmer Refillable Double-Junction Potassium Ion-Selective Electrode (27504-26)

The Cole-Parmer Refillable Potassium Ion-Selective Electrode (27504-26) is a precision laboratory sensor designed for fast, accurate measurement of free potassium ion (K+) concentration in aqueous solutions, agricultural runoff, environmental water, and food/beverage samples. Featuring a durable PVC polymer membrane sensing element and a refillable double-junction reference design, this electrode minimizes sample contamination and junction clogging when testing complex or high-ionic-strength matrices. The double-junction architecture allows users to choose customized outer reference filling solutions, preventing silver ions from reacting with sample components. Equipped with a standard BNC connector and a 3-foot cable, the 27504-26 seamlessly integrates with standard benchtop or portable pH/mV meters and dedicated ISE meters featuring a direct concentration readout option.

Technical Performance & Structural Attributes

• Polymer Membrane Technology: High-selectivity PVC membrane provides rapid millivolt response times and accurate potassium detection across wide concentration ranges.
• Refillable Double-Junction Reference System: Prevents precipitation and clogging at the liquid junction while prolonging electrode lifespan through simple reference electrolyte replenishment.
• Chemical-Resistant Epoxy Body: Durable outer body sleeve shields internal glass stem and reference assembly against mechanical impact and harsh field conditions.
• Universal BNC Connector: Includes a low-noise coaxial 3-foot cable terminated with a universal BNC plug for instant compatibility with analytical ISE/pH instrumentation.
• Optimized Interference Resistance: Formulated to deliver high selectivity for potassium ions in the presence of common background cations like sodium, ammonium, and calcium.

Product Specifications

• Catalog / Part Number: 27504-26
• Primary Manufacturer: Cole-Parmer
• Equipment Category: Analytical Sensor / Ion-Selective Electrode (ISE)
• Sensor Type: Potassium ($K^+$) Ion-Selective Combination Electrode
• Sensing Element Material: PVC Polymer Membrane
• Reference Junction Type: Refillable Double-Junction (Porous Ceramic)
• Measurement Range: 0.04 ppm to 39,000 ppm ($1 \times 10^{-6}$ M to 1.0 M)
• Slope / Nernstian Response: 54 to 59 mV per decade concentration change at 25 degrees C
• Interferences: Cs+, Rb+, NH4+, Tl+, Na+ (Selectivity coefficients apply)
• Operating Temperature Range: 0 to 40 degrees C (32 to 104 degrees F)
• Body Material & Dimensions: Epoxy Body; 12 mm OD x 120 mm Length
• Cable & Connector: 3 ft (0.9 m) Coaxial Cable with Standard Male BNC Plug

Key Benefits & Applications

• Agriculture & Soil Analysis: Essential for measuring available potassium levels in soil extracts, fertilizer formulations, and irrigation water.
• Food & Beverage Quality Control: Enables rapid quantification of potassium content in wine, fruit juices, dairy products, and processed food products.
• Environmental & Process Monitoring: Accurately monitors industrial wastewater effluent, river monitoring networks, and boiler feed water systems.

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